Wind and water motion producing machines have been around for several hundred years. We are quite familiar with the hundreds of windmills that dot the landscape of the Netherlands.
In considering wind power and water power producing apparatuses, one should recognize that there are two distinct types of operation involved. They are lift and drag. These terms refer to the motion involved in the apparatuses operations. In a lift device, the reaction to the wind energy is at right angles to the fluid flow, while in a drag apparatus it is not. In a drag device the apparatus responds parallel to the direction of the flow. If the fluid is flowing horizontally, it is seen the movement of the apparatus is horizontally. If the fluid is moving at another angle, then the apparatus moves at such angle. In a lift based device, such as the instant one, the resultant reaction force that transpires is at 90.degree. to the vector of the relative fluid flow. By the term relative fluid flow, it is meant the sector of the fluid flow as seen by an air foil.
It is well understood that a device constructed to operate in a drag configuration will have little or no operative capability in a lift configuration and vice-versa. Thus jet airplanes work on a lift principle and attempts to make them work in drag should fail. On the other hand, if a lift operating machine is place in a plane parallel to the fluid flow, it should stop operating.
In addition to the patents previously recited, the applicant herein is also familiar with such patents as that of Doak, U.S. Pat. No. 1,502,296, which operates in a drag configuration.
A water operative device known to applicant is disclosed in Swiss Pat. No. 313850 to Eberhard. In that device the blades that contribute to power output travel concurrently with the vector of the fluid flow 50% of the time and during such time contribute to power output. In the 2nd operational stage they move counter the flow. As will be seen from the discussion herein, the apparatus of the instant invention is able to operate effectively with fluid flowing in a vector from either face, such as in a tidal flow basin, a fact which could not transpire in the Eberhard unit.
Another patent known to applicant is that of Nance, U.S. Pat. No. 763,623, issued in 1904. In that patent, the foils in the second stage are so situated as to receive direct input of fluid as well as fluid directed from the front foils after glancing off of same. The instant apparatus operates significantly more effectively in that the second stage of the instant apparatus utilizes only fluid from the first stage as the operating fluid for the second stage. Nance suffers from a turbulent confluence of the air that is influenced by one foil to the next foil, due to the disruption of the laminar flow of fluid. Nance further suffers from the fact that with his two streams of fluid, instead of working together, by becoming confluent, they are disrupted and agitated, causing a confused fluid environment when the two streams strike each other, at the second stage.
The prior art considered in conjunction with the preparation of the present specification is as follows: U.S. Pat. No. 2,542,522; U.S. Pat. No. 2,939,017; U.S. Pat. No. 3,222,533; U.S. Pat. No. 3,473,038; U.S. Pat. No. 3,513,326; U.S. Pat. No. 3,720,840; U.S. Pat. No. 3,740,565; and U.S. Pat. No. 3,743,843. All of these prior art publications are to be considered as incorporated in to herein by reference.